import { API } from '../api.js';
import { DocumentQueueEntry } from './document-queue-entry.js'

/** @typedef {{selectedIDs: number[], allIDs: number[]}} DocumentQueueEventChangeSelectionDetails */
/** @typedef {CustomEvent<DocumentQueueEventChangeSelectionDetails>} DocumentQueueEventChangeSelection */

// TODO: Use LitElement, and use repeat directive, which also keeps the DOM state when shuffling elements around
export class DocumentQueue extends HTMLElement {
	/** @type {API|undefined} */
	#api;

	/** @param {API} api */
	set api(api) {
		this.#api = api;

		this.#api.addEventListener("queuedeleteat", /** @param {import("model").APIEvents["queuedeleteat"]} event */(event) => {
			this.queueDeleteAt(event.detail.indexA, event.detail.indexB);
		});
		this.#api.addEventListener("queueinsertat", /** @param {import("model").APIEvents["queueinsertat"]} event */(event) => {
			this.queueInsertAt(event.detail.index, event.detail.documents);
		});
		this.#api.addEventListener("queueshiftat", /** @param {import("model").APIEvents["queueshiftat"]} event */(event) => {
			this.queueShiftAt(event.detail.index, event.detail.offset);
		});
		this.#api.addEventListener("queuereplace", /** @param {import("model").APIEvents["queuereplace"]} event */(event) => {
			this.queueReplace(event.detail.documents);
		});
	}

	connectedCallback() {
		this.style.display = "flex";
		this.style.gap = "8px";
		this.style.flexDirection = "column";
		this.style.padding = "8px";
	}

	selectionInfo() {
		const children = Array.from(this.children);

		const result = {};
		result.selectedIDs = children.filter(/** @param {DocumentQueueEntry} value */ value => { return value.selected; }).map(/** @param {DocumentQueueEntry} value */(value) => { return value.queueEntry.id; });
		result.allIDs = children.map(/** @param {DocumentQueueEntry} value */ value => { return value.queueEntry.id; });

		return result;
	}

	updateSelection() {
		/** @type {CustomEventInit<DocumentQueueEventChangeSelectionDetails>} */
		const eventData = { detail: this.selectionInfo() };
		this.dispatchEvent(new CustomEvent("changeselection", eventData));
	}

	/**
	 * 
	 * @param {boolean} state 
	 */
	selectAll(state) {
		const children = Array.from(this.children);

		children.forEach(/** @param {DocumentQueueEntry} child */ child => {
			child.selected = state;
		});
	}

	/**
	 * Deletes a range of documents.
	 * @param {number} indexA // Start index.
	 * @param {number} indexB // End index. (Not included in the range).
	 */
	queueDeleteAt(indexA, indexB) {
		// Store positions.
		Array.from(this.children).forEach(/** @param {DocumentQueueEntry} child */ child => {
			child.prepareFLIP();
		});

		if (this.hasChildNodes()) {
			const children = this.children;
			for (let i = indexA; i < indexB; i++) {
				this.removeChild(children[i]);
			}
		}

		// Start FLIP animation.
		Array.from(this.children).forEach(/** @param {DocumentQueueEntry} child */ child => {
			child.doFLIP();
		});

		this.updateSelection();
	}

	/**
	 * Inserts a range of documents at the given index.
	 * @param {number} index
	 * @param {import('model').APIQueueEntry[]} documents
	 */
	queueInsertAt(index, documents) {
		// Store positions.
		Array.from(this.children).forEach(/** @param {DocumentQueueEntry} child */ child => {
			child.prepareFLIP();
		});

		documents.forEach(document => {
			if (this.hasChildNodes() || this.children.length === index) {
				const newChild = this.appendChild(new DocumentQueueEntry());
				newChild.api = this.#api;
				newChild.queueEntry = document;
				newChild.addEventListener("changeselection", e => this.updateSelection());
			} else {
				const newChild = this.insertBefore(new DocumentQueueEntry(), this.childNodes[index]);
				newChild.api = this.#api;
				newChild.queueEntry = document;
				newChild.addEventListener("changeselection", e => this.updateSelection());
			}
			index++;
		});

		// Start FLIP animation.
		Array.from(this.children).forEach(/** @param {DocumentQueueEntry} child */ child => {
			child.doFLIP();
		});

		this.updateSelection();
	}

	/**
	 * Replaces all documents currently in the list/queue.
	 * @param {import('model').APIQueueEntry[]} documents
	 */
	queueReplace(documents) {
		this.innerHTML = "";

		documents.forEach(document => {
			const newChild = this.appendChild(new DocumentQueueEntry());
			newChild.api = this.#api;
			newChild.queueEntry = document;
			newChild.addEventListener("changeselection", e => this.updateSelection());
		});

		this.updateSelection();
	}

	/**
	 * Shifts a single document entry by the given offset.
	 * @param {number} index
	 * @param {number} offset
	 */
	queueShiftAt(index, offset) {
		// Store positions.
		Array.from(this.children).forEach(/** @param {DocumentQueueEntry} child */ child => {
			child.prepareFLIP();
		});

		const child = this.children[index];
		child.remove();
		const newIndex = index + offset;
		if (!this.hasChildNodes() || this.children.length === newIndex) {
			this.appendChild(child);
		} else {
			this.insertBefore(child, this.children[newIndex]);
		}

		// Start FLIP animation.
		Array.from(this.children).forEach(/** @param {DocumentQueueEntry} child */ child => {
			child.doFLIP();
		});
	}
}

customElements.define("document-queue", DocumentQueue);